Color photography and sensitized material therefor



Nov. 19, 1929. I i J. E. THORNTON .,736,554

COLOR PHOTOGRAPHY AND SENSIT'ZED MATERIAL THEREFOR Filed July l, 1925 Figi.

NVENTOR.

Patenten Nov. 19,1929

UNITEDy STATES PATENT OFFICE JOHN EDWARD THORNTON, OF WEST. HAMPSTEAD, LONDON, ENGLAND, ASSIGNOR TO JOHN OWDEN OBRIEN, OF MANCHESTER, ENGLAND COLOR PHOTOGRAPHY AND: SEN SITIZED MATERIAL THEREFOR Application filed July 1, 1925, Serial No. 40,961, and in Great Britain August 2, 1924.`

Anegatives for the analysis of three colors being produced simultaneously by one lens and one exposure in two picture areas preferably side by side upon a double-width film, and

the positives comprising three colors beingproduced in two picture-areas preferabl upon one double-width thin film which 1s afterwards cut to form two thin films which are eventually superimposed and cemented to form one.

According to the invention the film material in the preferred form for either negatives or positives comprises a double-width film with two picture areas side by side, one area or half of the film lbeing provided during manufacture with -a two-color screen filter and the other area or half of the film with a singlecolori (non-pattern) filter coated with gsensitive emulsion so that one portion of the portion reproduce only the remaining color .of the original subject; in a modified form the negative film may have the picture areasalternating upon a single Width film.

Fig. 1 is a sectional plan of a strip of sensitized film material of double-width. On one half is formed a screen-filter of two colors, sich as blue-green and blue-violet. These colors are alternately interspersed and consist of extremely fine lines. In the drawing they are shownv coarse for clearness. On the other half is formed a full-tone color-filter (non-pattern) of a single color such as magenta, olfangea'ed, crimson or other suitable shade of red.

Fig. 2 is a sectional plan of part of Fig. 1 considerably enlarged.

Fig. 3 is a similar view showing the two colors on one half width arranged in squares.

Fig. 4: is a similar view showing the two colors on one halfwidt-h arranged in dots as a mosaic pattern. l

Fig. 5 is a transverse section on line 5 5 of lFig. 3.

Fig. 6 shows a modification in which the filters are arranged in alternating order upon la single-width strip, which is advantageous for use 1n single-width cameras, a screen filter of two colors being formed on one picture area consisting of extremely fine line and adjacent picture areas withra full tone color filter ofa single color.

References to other patents In my application Serial No. 711,251, filed May 5, 1924, I have described howl a picture in four colors vcan be made upon a doublewidth film by means of four negatives each representing a single color, and alternatively by means of two negatives each representing two colors; in either case vtwo are rinted upon one half of the double-width positive film and the other two upon the other half; the film is next severed toform two single strips which are then superim osed and'cemented to form one film in w ich the four colors are combined as onefour-color pic-` ture. I have also described therein how four image-spaces are filled with onl three colors, by duplicating one of the t ree, so that three-color pictures can be produced in one film by combination.

In the present invention it is essential to form two camera images in two separate picture-areas, and it is preferred to form them side-by-side upon double-,width negative film-material in one double-width camera, by one lens 'and a light-splitting device. The resulting negative then consists of a two-color mosaic (or screen) negative upon one half-width of film, and a complete section-image of the third color, in full-tone (or screenless) upon the other half-width. The invention is not however restricted to double-width material as will be understood from the alternatives hereinafter described, but such double-width material is-preferred;

In the present invention partial interception of light is avoided, because there are two images formed bytwo light-beams and each receives the fullest possible amount. A very full volume of light therefore passes direct from, the Elens through an orange-red or magenta-red filter, so that a full-tone negative duced from such negatives blue-green is represented by an image of full-tones; whilst the other colors ma enta-red and yellow are represented only y images of vbroken-tones (screen-mosaic pattern). l

Although this is the preferred arrangement of screens and colors, they may be arranged in any other combination to give a particular result in another preponderating color. For example it may be .desired to form the positive in red, green, and violet,

instead of red, blue, and yellow, in which case the negative and positive filters need modifying to give that result in the positive. By another modification the preponderating color for landscapes may be green, and for masses of fiowers or for gorgeous ceremonials crimson may preponderate, by suitable modification of the negative and positive filters. The description of colors is not necessarily exact, nor are the colors restricted to the combinations named, but they represent the .usual colors and combinations of standard practice.

'It is preferred to filter or 'represent the predominating color by the full-tone negative and the other two less predominating colors by the screen-mosaic negative. 1n the first described' examples the blue-green has been shown as recorded by the full-tone negative.

Manufacture of the film lmaterial Fhn-mate1aZ.-Tn carrying out the invention the material is constructed with'a base or support of Celluloid or other transparent equivalent, of preferably double-width and in the case of negative material about .005 inc hthick but-in the case of the positive material the celluloid support is only .003 of an inch thick.

,This is coated upon one side with an exceedingly thin layer of adhesive substratm of known type. ,l

' Upon this is coated a layer of colloid upon or in which the color-screen is to be formed.

If desired the color-screen layer and the substratum layer may be combined as one..

Or the screenmay` be formed direct in or uponthe celluloid ofthe support. I pre- 'fer however, the arrangement, of separate substratum and screen, both formed' of a colloid, and the following description therefore refers tosuch construction.

" Upon one half-width`f the'base or suport a color-screen for two colors-is formed y means of alternating dots, lines or other mosaic pattern in' exceedingly ne adjacent areas Figs. 2 to 4. This screen may consist of any two of the three colors, but green and violet are preferred. The construction and methods of manufacture are the same as those described in patent' specification Serial No.

711,254, filed March 15, 1924, but with the colors arranged instead as hereinbefore described.'

The other half-width of the base or support'is covered with a one-color filter, which is orange-red in color if the other screen is of green and violet.

The film is next coated all over with an exceedingly thin adhesive substratum layer superimposed upon the two filters.

The film is next again coated all over both filters with a layer ofhigh-speed gelatinosilver-bromide"panchromatic emulsion, superimposed upon the substratum.

When dry the negative material is then ready for use by exposing in the camera with .its'celluloid side to the lens, its sensitized side away from the lens and its orange-red or magenta-red filter covering one half and its mosaic screen green and violet filter covering the other half ofthe sensitized layer, such screens being between the support and sensitized layer, in the case of the positive material it is then ready for printing.

L. All three colors of both filters remain a pcrmanent par-t of the origin al material, and the single color-filter yis not dissolved vor removed, as in the Hess-Ives process.

After exposure or printing this film is developed, fixed, washed and treated exactly the saine as any ordinary monochrome film.

As the filters of the negative-film-material are complementary in color to those of the Aoriginal the ngatives will be complementary negatives, and this is rectied by the positives in which the colors will be again complementariy and will correspond to those of the ori gina Perfaraton and' registration Any desired system of perforation and registration'maybe used in lthe application of lthe present invention.

But l much prefer to make use of the onehole method for registration and the usual set of perforations for traction purposes.

To ensure accuracy of registration the highest possible standard of precision is necessary in the -perforating machinery and eX- treme vigilance upon the part of the operator attending to the perforating of both the negative film and the positivee Negatives produced upon negative-filmmaterial such as described may also be used for making three reproduced negatives, positives, or printing-cliches in monochrome, one from each color of the original negative, by the usual well-known methods of separation and reproduction. Positive prints can then be made from them, by any of the known processes, as three separate prints in three separate colors superimposed upon one support; or by printing upon two supports which are instead superimposed.

Or by suitable modification of the film-construction the negatives may be formed iny alternating order, by the same method of lightsplitting and simultaneous exposure, upon a single-width film of double length, from which printing-clichs can be made by copying on to two films upon which the two sets of images are arranged in direct instead of alternating sequence, or on to a double-width film.

In another modification the negatives can be made in alternating order one after thev other, in two exposures, upon such a singlewidth strip, and extracted by reproduction afterwards as above stated. By this method it is possible to make the two original 'negatives in an ordinary single-width camera, but the value of simultaneous exposure is lost and the defect known'. as fringing is thereby introducedl f Or two lenses may be used,` and both eX- posures made simultaneously, either upon a single strip, two single strips, or a double strip. This however introduces the defect known as parallax.

But these lesser perfect methods are useful in cases where cameras of these particular types only are available, and they still permit of the invention being used in making the negative and positive films.

lrVhat I claim as my invention and desire to protect by Letters Patent is 1. A sensitized film-material for kinematoi graph pictures having al two-color screen filter on one half width thereof and a singlecolor screen filteren the other half width.

2. Adouble-width sensitized film-material for kinematograph pictures having a twocolor screen filter upon one half Width and a single-color filter upon the other half width.

3. A sensitized film-material for kinematograph pictures having a two-color screen lter on one half the area thereof and a single color filter on the other half thearea thereof and a layer of panchromatic gelatine-silver- 

